Romanising Japanese just means turning Japanese words into pronouncable roman characters. Given that neither the letter L nor the letter R exist in japanese, it can't really be correct or incorrect either way. R sounds tend to be favoured when romanising, but that is just an arbitrary convention.
Yeah, well, the thing is, there are these "standards" that are supposed to be respected throughout romanizations of Japanese. You see, you're only taking into account the R/L sound compared to the English R and L sounds, but in many other languages (most major languages in Europe, for example), the Japanese R/L sounds much closer to an R than an L. That's why stuff like the Hepburn standard romanizations were built in the first place.
Thing is, you English-speaking guys have a really, really weird way of pronouncing R's